JPS6239896A - electronic musical instruments - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to musical tone synthesis, and more particularly to improvements for generating musical tones with ensemble effects.

SUMMARY OF THE INVENTION In an musical instrument that transmits at an average rate corresponding to the fundamental frequency of a musical tone producing a plurality of data words corresponding to the amplitudes of a corresponding number of equally spaced points defining one period of an audible musical sound waveform, an ensemble Computing means are provided for generating musical tones with effects. The calculation means performs a number of interpolation calculations whereby a series of interpolated waveform points are obtained from two different waveforms whose data points are addressed from the waveform memory at different memory advance rates.

Description of the Prior Art It is well known that the sound quality of electronic musical instruments can be enhanced by generating musical sounds with ensemble characteristics. or more musical tones. The motivation for this frequency arrangement is to mimic the ensemble effect produced by an ensemble of instruments that are not precisely in tune. Even when a group of violins are played in unison, the warm musical tone that is characteristic of these violins is produced by “R!14 (
out-of-tune)” This is the nature of the ensemble.

Various arrangements have been used to electronically generate two simultaneous musical tones that are one degree out of tune from each other. A simple arrangement simply uses two tone generators and uses detuned clocks to drive the tone generators. This array is.

It suffers from the practical problem of implementing two independent clocks that must be very slightly am and cannot vary in frequency independently as atmospheric conditions change.

Boa Celeste (ca4) in 1 computer towel gun
US Pat. No. 3,809.
No. 792 discloses a system for generating a Boiseresto version of an ensemble effect by calculating the amplitude of successive sample points of a musical waveform and converting the amplitude to a musical tone as the calculation is performed in real time.

Each amplitude point is computed during regular time intervals by individually computing and combining at least two sets of discrete Fourier components.

The first set includes harmonically related components, generally the fundamental frequency and upper back of the true pitch of each keyboard selection note. The second set of components is generated with a frequency shifted slightly higher than the first set of frequencies.

U.S. Patent No. 4112.80!1 entitled 'Ensemble and non-It6 harmonic generation method in polytone synthesizer'
No. (Japanese Patent Application No. 51-145162), the main data set is subjected to dt calculation, the main data set is transferred to a buffer memory, and the content of the buffer memory is repeated in real time to convert it into an analog tone waveform, thereby producing a double tone. An apparatus for generating an ensemble effect in a multitone synthesizer of the type that generates musical tones is disclosed. A large number of primary data sets are iterated by computing a general Ri-Rier type algorithm using stored sets of harmonic coefficients.

It is created without any relation to musical tone generation. The phases of these main data sets are generated with time-varying phase shifts to generate detuned ensemble effects. The phase-shifted raw data sets are combined and transferred to backup memory.

U.S. Patent No. 4.205.580 entitled 'Ensemble Effect Apparatus for Electronic Musical Instruments'
55) discloses a device for generating ensemble effects in a polyphonic synthesizer by providing a primary data set of words whose values correspond to the relative amplitudes of equally spaced points along one period of a musical sound waveform. has been done. These values are sequentially transferred to a DA converter during repeating cycles at a rate proportional to the pitch of the desired musical note, converting the main data set into an audio signal of the desired waveform and pitch. An ensemble effect is created by transferring the words of the main data set to the second set at the same clock rate, but in the second set by removing one data point or repeating it once.

U.S. Pat. No. 4,353,279 entitled ``Ensemble Musical Sound Generator in Electronic Musical Instruments'' discloses that the fundamental frequency has been removed and the relative amplitudes of points equidistantly spaced along one period of a musical sound waveform are calculated. A system is disclosed for generating ensemble effects in a digital tone generator by providing a primary data set of words having values corresponding to . These values are iteratively read from memory to generate a first analog tone. A second analog musical tone is generated by multiplying a data set corresponding to the fundamental frequency by a low frequency sinusoidal waveform set of points. The first and second analog tones are summed to create a tone with an ensemble effect.

US i'Fl No. 4.476.691 entitled 'Selectable Ensemble Effects in Electronic Musical Instruments'
G (D each has many synthesized sounds (oompos+lte)
A system is disclosed for generating an ensemble effect in a digital tone generator by implementing a plurality of tone generators having an ensemble tone effect created by summing the tones). This tone generation is accomplished by repeatedly accessing a memory containing a set of data points defining one period of a preselected tone waveform. Each tone generator is implemented by selecting a corresponding set of data points read from memory.

This selection logic is controlled by a selection gate and a comparator responsive to the frequency of the associated actuated keyboard switch.

Summary of the Invention U.S. Patent No. 4,085,644
In polytone synthesizers of the type described in 19), calculation cycles and data transfer cycles are performed separately and repeatedly to provide data that is converted into a musical sound waveform with an ensemble effect. Each of them is 2
A plurality of computation cycles consisting of a subset of one subcomutation cycle is performed. During a first subcombination cycle, a first main data set of points defining the period of a first musical waveform stored in a first waveform memory is calculated, and during a second subcombination/cycle A second main data set of points defining the period of the second musical waveform stored in the second waveform memory is calculated therein.

A frequency number corresponding to the actuated keyboard switch is generated. This frequency number is used to implement a fractional frequency generator by periodically adding the frequency number to the accumulator of the adder-accumulator combination. The integer part of the accumulated phase of the frequency number is addressed out from the first waveform memory that stores one point of the first main data set, and the data value is addressed out from the second waveform memory that stores one point of the second main data set. Used to address out data values. The fractional portion of the accumulated frequency number is used to calculate a first interpolated data point between two consecutive data points read from the first waveform memory. Similarly, the same fractional portion is used to calculate a second interpolated data point between two consecutive data points read from the second waveform memory.

An offset or detuned frequency number is generated by modifying the original frequency number. The offset frequency number is also used in the fractional frequency generator to create a second accumulated frequency number.

This second accumulated frequency number is used to address data points from the second waveform memory and calculate a sixth interpolated data point between two consecutive data points read from the second waveform memory.

The third interpolation process consists of successive first interpolation points, successive second interpolation points,
An interpolation is performed between the interpolation point and a fifth consecutive interpolation point to generate a series of data points corresponding to a musical note with an ensemble effect.

This series of data points is converted into an analog signal.

This analog signal generates an audible musical tone.

DETAILED DESCRIPTION OF THE INVENTION The present invention is disclosed in U.S. Pat.
85.644 (Japanese Patent Application No. 51-93519), the aim is to improve the sound quality produced by the system.

This patent is mentioned here for reference only.

In the description that follows, all elements of the system described in the patent, which is mentioned by reference, are referred to as identically numbered elements that appear in U.S. Pat. No. 4,085,644, which is also mentioned by reference. Identified by digits.

Figure 1 is for reference only, U.S. Pat. No. 4,085.
．． 644 (% Asama 51-95519), an embodiment of the invention is described as a modification and addition to the system described in No. 644 (% Asama 51-95519). This preferred embodiment is.

A computation cycle is started to compute the main data set and then register the mate register (not r@g1mt) associated with the single tone generator to which the main data set is assigned.
This is an example of transferring to @r). As soon as the transfer of the main data set is completed, a second itt computation cycle is immediately started to calculate the unique main data set for the second assigned tone generator. This sequence of calculation cycles followed by transfer cycles continues until a new main data set has been calculated and transferred to each assigned tone generator. The complete Kt calculation and transfer process is then repeated, so that each tone generator is individually and continuously supplied with its own constantly updated main data set. Unique ensemble effects can be implemented for the musical tone generator.

As described in the patent mentioned by reference above, the polytone synthesizer includes an array of musical instrument keyboard switches 12. When one or more keyboard switches change their switch state and are actuated (into the 1 on' switch position), the tone detection and allocation device f14 changes the state to the actuated state and encodes the detected keyboard switch t. 1 and stores the corresponding note information about the activated key switch. A tone generator included in the system block labeled tone generator 104 is assigned to each actuated key switch using information generated by tone detection and assignment device 14.

A suitable arrangement for the tone detection and assignment subsystem is described in U.S. Pat.
52). This patent is included here for reference.

When one or more key switches are actuated, execution control circuit 16 initiates a series of repeating discrete calculation cycles;
This is followed by the associated transfer cycle. Each computation cycle is divided into two subcomutation cycles. During the first sub-combination cycle, a plurality of harmonic wave suppression coefficient memories 26, 126,
226...0 A first main data set is #calculated using one set of cylindrical harmonic coefficients stored in one. This first main data set is stored in the main register 34. Second
During the subcommittee J/cycle, the first
A second set of harmonic coefficients, which is usually different from the one set of harmonic coefficients used for the LTT calculation of the main data set, is used to calculate the second set of harmonic coefficients.
The main data set is calculated. This second main data set is stored in main register 164.

Reference is made to U.S. Pat. No. 4.085.644.
No. (% Asama 51-93519).

Harmonic counter 20 is initialized to its minimum count state, ie, zero count state, at the beginning of each calculation cycle. Each time the word counter 19 is incremented by the execution control circuit 16 and returns to its minimum count state, i.e., the zero count state, due to its modulo counting implementation, the execution control circuit 16 generates a signal which is incremented by the harmonic counter 20. Increment the count state. word counter 1
9 is implemented to count modulo 64, which is the number of data words making up the main data set. The harmonic counter 20 is equal to the maximum number of harmonics corresponding to the number of words in the main data set, which defines points equidistantly spaced for one period of the generated musical tone. = 64/2
It is implemented to count 32.

At the beginning of each sub-commutation cycle.

The accumulator of adder-accumulator 21 is initialized to a zero value by execution control circuit 16 . Each time word counter 19 is incremented.

Adder-accumulator 21 adds the current count state of harmonic counter 20 to the sum contained in the accumulator. This addition is performed modulo 64.

The contents of the accumulators in adder-accumulator 21 are used by memory address decoder 25 to access trigonometric function values from sine wave function table 24. This sine wave function table stores the values of the trigonometric function gln(2πθ/64) for 0<θ<64 in the interval -
It is advantageous to implement it as a memory. D is a table decomposition constant (r・so#tion constant
).

The memory address decoder 25 responds to the count state of the harmonic counter 20 and stores a plurality of harmonic coefficient memo IJ 26.
, 126 and 226 simultaneously. Although only three such harmonic coefficient memories are explicitly shown in FIG. 1, it is clear from the discussion below that any number of such memories can be incorporated into a musical tone generation system. I'll go.

During the first subcombination cycle.

In response to a signal from selection control circuit 102, data selection circuit 101 selects a harmonic coefficient read from one of a set of harmonic coefficient memories. 1 selection control circuit 1 during the second subcombination cycle
In response to the signal from 02, the data selection circuit 101 selects the first
Selecting harmonic coefficients read from another harmonic coefficient memory other than the selected memory during the subcombination cycle.

Selection control circuit 102 can vary the selection of harmonic coefficient memories as a function of time. The selection control circuit 102 selects a pair of harmonic coefficient memories 26 and 126 when the tone detection and assignment device 14 detects that the key switch has been actuated.
It is advantageous that it can be implemented to select. After a certain amount of predetermined time has passed, )@selection control circuit 10
2 selects output data read from harmonic coefficient memories 126 and 226. This number can continue and cycle through the available harmonic coefficients in pairs.

Multiplier 28 multiplies the three-jump value read from sine wave function table 24 by the high peak coefficient selected by data selection circuit 101 in response to the signal provided by 1 selection control circuit 102.

During both subcomutation cycles, data words of the main data set are read simultaneously from main register 34 and main register 134 in response to the counting state of word counter 19.

During X1JiJl of the first subcombination cycle, data selection circuit 103 selects a data value read from main register 54 in response to a command signal from execution control circuit 16. This selected data value is added to the product value generated by multiplier 28 by adder 35.

Next, the data selection circuit 106.

The summed value is stored in main register 34 at the same address from which the original data value was read.

Similarly, during the second subcombination cycle, data selection circuit 106 selects a data value read from main register 134 in response to a command signal from execution 111 control circuit 16. This selected data value is added by adder 33 to the product value generated by the multiplier. Data selection circuit 103 then stores the summed value in main register 134 at the same address from which the original data value was read.

Once both subcomutation cycles are completed, a transfer cycle begins, during which the first main data set stored in main register 34 and the second main data set stored in main register 134 are transferred. ,
It is transferred to a note register, which is a component of each of a plurality of tone generators included in the system block labeled tone generator 104.

Details of the interpolation subsystem used to generate the desired ensemble effect from the first and second primary data sets are shown in FIG. Although FIG. 2 only explicitly shows one tone generator, it is clear from the description that the elements can be increased to provide any desired number of tone generators.

The present invention generates an ensemble effect by combining interpolation for waveform addressing using accumulated frequencies and interpolation between two different waveforms. The pitch or fundamental frequency of the musical tones produced is determined by assigning a frequency number to each actuated key switch on the instrument's keyboard switch array. This frequency number is sequentially added to the contents of the accumulator. The accumulated frequency number has an integer part and a decimal or fractional part.

The integer part contains a set of most significant bits of the binary representation for the accumulated frequency number.

The fractional part is the least significant set of bits of this same binary representation. The integer portion is used to address out waveform data points stored in waveform memory. The fractional part is used to perform interpolation for fractional differences between two consecutive waveform points.

Let Aj denote the stored waveform data point corresponding to the integer part of the accumulated frequency. The value of the interpolated waveform Ai corresponding to the accumulated frequency is given by the following formula: AI "" Fl (Aj + - Aj ) +
Aj=FIAj+1+(1-FT)Aj
Equation 1 However, Fj indicates the fractional part of the accumulated frequency number. Also, a second waveform set of data points includes a second waveform set of data points.
Waveform mesori also exists. The interpolated data values obtained from this second waveform memory corresponding to the same frequency number are given by the following formula: Bi = F'l
Bj + + (1-Fl) Bj
Equation 2 A third interpolation is performed between the interpolated data values phantom and 810. Since P indicates the fractional value of the third interpolation.

The resulting interpolated value is given by the following formula: C4= (Bi −AI )P+AI
By combining Equation 1 and Equation 2, Al and B1 can be removed from Equation 6 to obtain the following equation: C+ = PFI J + P (1-FT) + (1
-P)F+Aj+(1-P)(1-Fj)Aj Equation 4 The waveform seen by the sequence of points C1 corresponds to a waveform with a fundamental frequency determined by the assigned frequency number.

The second frequency number is found by adding an offset value to or subtracting an offset value from the true frequency number assigned to the actuated keyboard switch.

This second frequency number is also successively added to a second accumulator to form a second accumulated frequency number. The second accumulated frequency number is also used to read waveform sample points from the second waveform. Another interpolation is performed on these waveform sample points.

The following interpolated value is obtained: Bk = F2Bmt+1 + (1-F2)B
m Equation 5 Corresponding to Equation 3, the new waveform interpolation value corresponding to the second cumulative frequency number is as follows: 202 ''' (Bk-At) P
By combining Equation 6, Equation 21, Equation 4, and Equation 5, we can obtain the following result: C2= PF2 Btn 1 ← P(1-F2)B
m+ (1-P)F+Aj+-+ +(1-P) (
1-Fl ) A2 Formula 7 points C1 and C2
are summed as they are computed in an evenly spaced time order, the net result being an ensemble effect of two waveforms with different fundamental frequencies. It is noted that the last two terms in Equations 4 and 7 are the same because they are the same result of double interpolation of the first waveform set of data points.

When the tone detection and assignment device 14 detects that a keyboard switch has been actuated, the corresponding frequency number is read from the frequency number memory 119. Frequency number memory 119 may be implemented as a fixed addressable memory (RAM) containing data stored in binary format having values of 2-(M-N/12), where N=N= It has a value range of 1, 2, . . . 0M, where 9M is equal to the number of key switches on the instrument keyboard.

The frequency number represents the ratio of the frequency of the generated musical tone to the frequency of the system's logical clock.

A detailed explanation of frequency numbers is provided in U.S. Pat.
No. 6 (Japanese Patent Application No. 53-1041).

This patent is incorporated herein by reference.

The frequency number read from the frequency number memory is stored in the frequency number rack y-106.

In response to timing signals generated by logic clock 110, the frequency numbers contained in one frequency number rat y-106 are successively added to the contents of an accumulator contained in adder-accumulator 109. The contents of the accumulator are the accumulated sum of frequency numbers.

During the transfer cycle associated with the tone generator explicitly shown in FIG. The included second main data set is copied into the note register 147.

In response to the integer portion of the accumulated frequency number contained in adder-1 accumulator 109, memory 7 address coder 112 reads two consecutive data words from note register 65, which data words are input as data inputs. It is applied to interpolation circuit 114. This memory reading is carried out modulo the number of memory addresses contained in note register 55. Therefore, if the lowest memory address word is read, the second read word of the pair is read from the lowest memory address.

Data interpolator 114 uses the fractional part of the accumulated frequency number contained in adder-accumulator 109 for the fractional value F1 explicitly shown in Equation 4.

The value of P required for interpolation between two waveforms is determined by the selection control circuit 1.
02. The data interpolation circuit 114 is expressed by formula 4.
Perform calculations corresponding to the last two terms. It has already been shown that these are the same as the last two terms in Equation 7.

Frequency offset adder 107 adds a fixed predetermined number to the frequency number read from frequency number memory 106. The modified frequency number is stored in frequency number wrap 108.

Alternatively, a subtraction operation may be used instead of an adder to subtract a predetermined number from the frequency number read from frequency number memory 119 to provide a modified or detuned frequency number. Another alternative is to vary the frequency offset number increments as a function of the true frequency number read from frequency number memory 119.

The modified or detuned frequency number stored in the frequency template y-ID 8 is continuously added to the contents of the accumulators of the adder-accumulators 111 in response to timing signals provided by the logic clock 110. In response to the integer portion of the accumulated frequency number of adder-accumulator 111A, memory address decoder 115 reads two consecutive data words from note register 147. This read data word is provided to interpolation circuit 116 as input data. This memory read is also performed modulo the number of memory addresses contained in note register 147.

In response to the integer portion of the accumulated frequency number in adder-accumulator 111, memory address decoder 112 reads two consecutive data words from note register 147. The read data is given to data interpolation circuit 115 as input data.

Data interpolator 115 calculates the first two terms of C1 shown in Equation 4. The data interpolation circuit @116 calculates the first two terms of C2 shown in Equation 7.

The results of the calculations of data interpolators 115 and 116 are summed by adder 117.

The output data value calculated by the data interpolation circuit 114 is shifted to the left in the data interpolation circuit 114, and its value is doubled. The result is added to the adder 118 by one person.
given to. The second manual input to the adder 118 is the adder 11
This is the output from 7. It is converted into an adder 118 signal.

The resulting analog signal is converted into musical tones by a music system 11 consisting of an amplifier and speaker combination.

FIG. 5 shows details of the system logic of data interpolation circuit 14. The one's complement circuit 140 performs one's complement binary operation on the binary value of the interpolation parameter P given by the selection control circuit 102. The result of this operation is the decimal value i-p
is the binary value corresponding to . In the one's complement cycle, $14 is a one's complement binary operation of the fractional part of the accumulated frequency number F10 contained in the adder-accumulator 109.

The result of this operation is a binary value corresponding to the decimal value 1-Fl.

Multiplier 142 multiplies the outputs from the two one's complement operations to yield the product term (1-P)(1-Fj).

Multiplier 145 uses the first term of the pair of data values read from note register 35 to form the product of the output of multiplier 142 . Multiplier 155 multiplies Fl and 1-P to yield the product term (1-P)Pi. Multiplier 156 multiplies the second term A of the pair of data values read from note register 35.
Create a product of the outputs of multiplier 155 using j-N. Adder 157 sums the product values generated by multipliers 143p and 156. The sum value generated by adder 157 is Equation 4 and the last two terms of the seventh. The left shift circuit 158 has one 2
Performs a binary left shift of the hex bit position and doubles the input data value.

FIG. 4 shows details of the system logic of data interpolation circuit 115. The purpose of data interpolation circuit 1150 is to calculate the first two terms on the right side of Equation 4. Multiplier 146 multiplies the interpolation parameter P provided by selection control circuit 102 and Fl, which is the fractional part of the accumulated frequency number contained in adder-accumulator 109 . Multiplier 1
48 creates the product PF, Bj, . 8j□1 is read from the note register 147 in response to the memory address decoder 112 and is the second term of the ii pair of data values.

Term 1-F1 is generated by one's complement circuit 145 by performing a one's complement binary operation on fractional value F1.

Multiplier 147 produces a product value of P(1-F,). Multiplier 1
49 creates a product value P(1-PH)Bj. Bj is output from the mate register 147 in response to the memory address decoder 112.
is the first term of a pair of data values read from . Adder 150 sums the output product values from multiplier 148 and multiplier 149 to generate a data value corresponding to the first two terms on the right side of Equation 9.4.

Data interpolator 116 is implemented in a manner similar to that for interpolator 115.

The present invention is not limited to musical tone generation systems that calculate primary data sets corresponding to musical waveforms. An alternative system is one that uses memory to store preselected waveforms. This general type of musical tone generation is described in US Pat. No. 3,515, entitled 'Digital Organ'.
No. 792. This patent is included here for reference.

FIG. 5 shows an alternative embodiment of the invention. Each of the plurality of waveform memos IJ 121-123 stores a preselected set of data points corresponding to a musical tone waveform. In response to signals generated by selection control circuit 102, data selection circuitry selects data points read from two of the waveform memories. Memory read circuit 129 is a memory addressing subsystem used to simultaneously read nine waveform data points stored in multiple waveform memories. The selected sets of waveform data points are stored in note register 55 and note register 147. The remaining components of the tone generation system, including the subsystem for reading data from the two note registers and the data interpolation circuit, are the same as shown in FIG. 2 above.

Embodiments of the present invention will be listed below.

1. The above musical instrument.

With multiple keyboard switches.

and detecting means for encoding a detection signal in response to a key switch t of the plurality of keyboard switches t to indicate a closed key switch.

Device according to claim 1.

Z. The harmonic data selection means.

a selection control signal generator that generates the selection control signal;

'! of the plurality of harmonic coefficient memory means in response to the selection control signal. 81 data selection circuit for selecting a harmonic coefficient from among the harmonic coefficients read from the memory means and selecting a harmonic coefficient from the harmonic coefficients read from the second memory means of the plurality of harmonic coefficient memory means; including.

Device according to claim 1.

The harmonic addressing means is:

A clock that provides a tie (y signal).

a word counter that counts the timing signal modulo the number of the plurality of data words corresponding to one cycle of the musical sound waveform;

a harmonic counter that is incremented each time said word counter returns to its minimum count state;

in response to a count state of the harmonic counter.

and a harmonic address decoder for reading out 1% harmonic coefficients from the plurality of harmonic coefficient memory means.

Device according to claim 1.

4. The calculation means.

an adder-accumulator for continuously adding the count state of the harmonic counter to the contents of an accumulator in response to a Moeki timing signal;

A sine wave function table that stores multiple trigonometric sine wave function values.

and address decoder means for generating an address signal in response to the contents of the accumulator.

sine wave function addressing means for reading trigonometric function sine wave function values from the sine wave function table in response to the address signal;

in response to the trigonometric function value read from the sine wave function table and the harmonic coefficient selected by the harmonic data selection means, and corresponds to the amplitude of equally spaced points defined by the first waveform of the musical tone. calculating and storing said plurality of data words in said first waveform memory means; calculating and storing said plurality of data words corresponding to amplitudes of equally spaced points defining a second waveform of a musical note; and main data set calculation means for storing in the waveform memory means.

Apparatus according to paragraph 5 above.

5. The detection means.

and frequency number means for generating a frequency number in response to each of the detection signals.

Apparatus according to paragraph 1 above.

& The first memory addressing means.

The first step is to continuously add the generated frequency numbers to the contents of the accumulator to produce the cumulative frequency number s1.
Frequency adder--accumulator means.

first memory address decoder means for discharging a data word from said first waveform memory means at an address corresponding to a preselected number of most significant bits of said first counting frequency number.

Apparatus according to paragraph 5 above.

7. The second memory addressing means.

a frequency number offset generator for modifying the generated frequency number by a preselected value;

a second frequency adder-accumulator means for successively adding said modified frequency number to the contents of the accumulator to produce a second accumulated frequency number;

second memory address decoder means for reading a data word from said second waveform memory means at an address corresponding to a preselected number of most significant bits of said second accumulated frequency S/bar.

Apparatus according to paragraph 6 above.

a. The waveform combination calculation means.

responsive to a preselected number of least significant bits of the first accumulated frequency number;
first interpolation means for calculating from two consecutive data points read from the waveform memory means;

Said 's1 accumulated laps l! ! second interpolation means responsive to said preselected number of least significant bits of the number number for calculating a second interpolated data point from two consecutive data points read from said second waveform memory means;

third interpolation means for calculating a first composite interpolated data point from the first interpolated data point and the twenty-second complementary data point in response to the selection control signal;

In response to a preselected value of the least significant bit of the second accumulated frequency number, a fifth interpolated data point is added to the second
fourth interpolation means for calculating from two consecutive data points read from the waveform memory means;

fifth interpolation means for calculating a second composite interpolated data point from the first interpolated data point and the third interpolated data point in response to the selection control signal;

interpolating and combining means for producing said series of interpolated data values by combining each of said first composite interpolated data points and each of said second composite interpolated data points.

Apparatus according to paragraph 7 above.

9. The above musical instrument.

Detection means responsive to closure of one of the plurality of keyswitches to encode a detection signal to indicate the closed keyswitch.

and frequency number means for generating a frequency AR pulse in response to each of the detection signals.

Device according to claim 2.

10. The waveform data selection means.

a selection control signal generator that generates the selection control signal;

a data selection circuit responsive to the selection control signal for selecting data points read from the plurality of waveform memory means and storing them in the first waveform storage means and the second waveform storage means.

Device according to claim 2.

11. The first memory addressing means.

a first step for successively adding said generated frequency numbers to the contents of an accumulator to produce a first accumulated frequency number;
Frequency adder--accumulator means.

first memory address decoder means for reading a data word from said first waveform storage means at an address corresponding to a preselected number of most significant bits of said first M&amp;M frequency number.

Apparatus according to paragraph 9 above.

1z The js2 memory addressing means.

a frequency number offset generator for modifying the generated frequency number by a preselected value;

a second frequency adder-accumulator means for successively adding said modified frequency numbers to an accumulator to produce a second accumulated frequency number;

a second memory address decoder for reading a data word from the second waveform storage means at an address corresponding to a preselected nine most significant bits of the second series frequency number.

The device according to Section 1, Part 11.

16. The waveform combining means.

a first calculating a first interpolated data point #i from two consecutive data points read from said first waveform memory means in response to a preselected number of least significant bits of said 's1 accumulated frequency number; with interpolation means.

second interpolation means for calculating a second interpolated data point from two consecutive data points read from said second waveform memory means in response to a preselected number of least significant bits of said first pA calculation frequency number; and.

A first composite interpolated data point is selected from the first interpolated data point and the second interpolated data point in response to the selection control signal.
t)? : The third means of interrogation.

a sixth interpolated data point in response to a preselected number of least significant bits of the second accumulated frequency number;
fourth interpolation means for calculating from two consecutive data points read from the waveform memory means;

fifth interpolation means for calculating a second composite interpolated data point from the first interpolated data point and the third interpolated data point in response to the selection control signal;

interpolating combining means for producing the series of interpolated data values by combining each of the first composite interpolated data points and each of the second composite interpolated data points.

Apparatus according to paragraph 12 above.

[Brief explanation of drawings]

FIG. 1 is a system block diagram of a musical waveform generator. FIG. 2 is a system block diagram of the interpolation subsystem that generates the ensemble. FIG. 5 is a system block diagram of the data interpolation circuit 114. FIG. 4 is a system block diagram of the data interpolation circuit 115. FIG. 5 is a system block diagram of an alternative system embodiment. In Figures 1 and 2. 11 is the sound system. 12 is the instrument keyboard switch. 14 is a tone detection and assignment device. 16 is an execution control circuit. 19 is a word counter. 20 is a cylindrical axial wave counter. 21.111 is an adder-accumulator. 22 is the gate. 26 is a memory address decoder. 24 is a sine wave function table. 25 is a memory address decoder. 26. 126 and 226 are harmonic coefficient memories. 28 is a multiplier. 65 is an adder. 34 and 134 are main registers. 35.147 is the note register. 47 is a DA converter. 101 is a data selection circuit. 102 is a selection control circuit. 103 is a data selection circuit. 104 is a musical tone generator. 106 is the frequency number rat t. 107 is a frequency offset adder. 108 is the frequency number wrap. 109 is an adder-accumulator. 110 is a logic clock. 112.115 is a mesori address decoder. 114.115.116 is a data interpolation circuit. 117.118 is an adder. 119 is frequency number memory.

Claims (1)

[Claims] 1. Computing and generating a plurality of data words corresponding to the amplitudes of equally spaced points defining a musical sound waveform from a preselected set of harmonic coefficients in a series of computational cycles. a plurality of harmonic coefficient memory means each storing a preselected harmonic coefficient, the harmonic coefficient memory means having a combination of musical instruments that sequentially transfer and convert into a musical sound waveform at a speed proportional to the pitch of the musical tone; and a first waveform memory means. a second waveform memory means; a harmonic addressing means for reading harmonic coefficients from the plurality of harmonic coefficient memory means; and a harmonic addressing means for reading harmonic coefficients from the plurality of harmonic coefficient memory means; harmonic data selection means for selecting from a subset of coefficient memory means; and responsive to said selected and read harmonic coefficients, calculating said amplitudes of equally spaced points defining a first waveform of a musical tone; calculation means for storing in the first waveform memory means, calculating the amplitudes of equally spaced points defining a second waveform of musical tones, and storing the amplitudes in the second waveform memory means; and the first waveform memory means. a first memory for reading data words stored in said second waveform memory means at said preselected first memory address advance rate; and for reading data words stored in said second waveform memory means at said preselected first memory address advance rate. addressing means; second memory addressing means for reading data words stored in said second waveform memory means at a second preselected memory advance rate; waveform combination calculation means for calculating a series of interpolated data values from said data word read from said memory means and said data word read from said second waveform memory means; and converting means for generating said musical tone having an effect. 2. In combination with a keyboard-operated musical instrument having a plurality of key switches, a plurality of waveform memory means each storing a set of data points corresponding to a preselected musical sound waveform; and said plurality of waveform memory means. waveform addressing means for reading data points from the plurality of waveform memory means; first waveform storage means; second waveform storage means; Waveform data for storing read data points in the first waveform storage means and storing data points read from a second waveform memory means of the plurality of waveform memory means in the second waveform storage means. selecting means for reading data words from said first waveform storage means at a preselected first memory address advance rate and reading data words from said second waveform storage means at said preselected fourth memory address advance rate; first memory addressing means for reading words; and second memory addressing means for reading data words from said second waveform storage means at a preselected second memory address advance rate.
memory addressing means and, responsive to said selection control signal, generating a series of interpolated data values from said data word read from said first waveform storage means and said data word read from said second waveform storage means; An apparatus for generating a musical tone having an ensemble effect, comprising: a waveform combination calculating means for calculating the series of interpolated data values; and a converting means for converting the series of interpolated data values into an analog signal to generate the musical tone having an ensemble musical tone effect.